Hockey stick blade

ABSTRACT

A hockey stick blade comprising a shank and a blade element having a front surface and a rear surface. The blade comprises a core of synthetic material extending along a longitudinal axis, the core comprising a blade element portion. The blade also comprises a layer of fibers recovering the core of synthetic material and a layer of thermoplastic material recovering the layer of fibers.

FIELD OF THE INVENTION

The present invention relates to a hockey stick blade comprising frontand rear surfaces having a layer of thermoplastic material.

BACKGROUND OF THE INVENTION

Typical hockey stick blades or replacement blades are generally made ofa wooden core reinforced with one or more layers of synthetic materialsuch as fiberglass, carbon fibers or graphite. The core of the blade mayalso be made of a synthetic material reinforced with layers of fibersmaterial. The layers are usually made of woven filament fibers,typically soaked in a resin and glued to the surfaces of the core of theblade. Expandable fibers braids may also be used for recovering the coreof the blade.

Canadian Patent Application 2,228,104 discloses a hockey stickcomprising a wooden shaft and a composite blade with a pre-form coremade of thermoplastic polyurethane foam. The pre-form core is recoveredof braided glass socks and layers of reinforcing materials.

U.S. Pat. No. 5,048,878 discloses an expanded polyvinyl chloride foamcore stick wherein the core is covered with meshes of fiberglass orcarbon fibers.

U.S. Pat. No. 5,333,857 discloses a hockey stick comprising a shaftsection, a blade section and a heel section forming the connectionbetween the blade and shaft sections. The stick comprises a core made ofsynthetic foam having a first density for the shaft, a second densityfor the heel and a third density for the blade. The core is covered withthree layers of woven materials.

There is a demand for an improved hockey stick blade having a betterimpact resistance.

SUMMARY OF THE INVENTION

As embodied and broadly described herein, the invention provides ahockey stick blade with a shank and a blade element having a frontsurface and a rear surface. The blade comprises a core of syntheticmaterial extending along a longitudinal axis, a layer of fibersrecovering at least partially the core of synthetic material and a layerof thermoplastic material recovering at least partially the layer offibers. The layer of thermoplastic material forms part of one of thefront and rear surfaces of the blade element.

As embodied and broadly described herein, the invention provides ahockey stick blade with a shank and a blade element having a frontsurface and a rear surface. The hockey stick blade comprises a core ofsynthetic material extending along a longitudinal axis and a layer offibers recovering at least partially the core of synthetic material. Oneof the front and rear surfaces of the blade element comprises a layer ofthermoplastic material that recovers at least partially the layer offibers.

Other objects and features of the invention will become apparent byreference to the following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the embodiments of the present invention isprovided herein below, by way of example only, with reference to theaccompanying drawings, in which:

FIG. 1 is a perspective view of a hockey stick blade constructed inaccordance with the invention;

FIG. 2 is a perspective view of the blade of FIG. 1 with layers beingpeel off;

FIG. 3 is a perspective view of first and second core portions used inthe construction of the blade of FIG. 1;

FIG. 4 is a cross sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a perspective view of the first and second core portions ofFIG. 4 with first and second fibers braids used in the construction ofthe blade of FIG. 1;

FIG. 6 is a perspective view of the first and second core portions andfirst and second fibers braids of FIG. 5 with a further fibers braidused in the construction of the blade of FIG. 1;

FIG. 7 is a perspective view of the first and second core portions andthe fibers braids of FIG. 6 with a further fibers braid used in theconstruction of the blade of FIG. 1;

FIG. 8 is a perspective view of the blade of FIG. 1 before the moldingoperation;

FIG. 9 is a cross sectional view taken along line 9-9 of FIG. 8;

FIG. 10 is a perspective view of the preformed blade of FIG. 8 withsheets of thermoplastic material used in the construction of the bladeof FIG. 1; and

FIG. 11 is a perspective view of a mold and the preformed blade with thesheets of thermoplastic material.

In the drawings, the embodiments of the invention are illustrated by wayof examples. It is to be expressly understood that the description anddrawings are only for the purpose of illustration and are an aid forunderstanding. They are not intended to be a definition of the limits ofthe invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

To facilitate the description, any reference numeral designating anelement in one figure will designate the same element if used in anyother figures. In describing the embodiments, specific terminology isresorted to for the sake of clarity but the invention is not intended tobe limited to the specific terms so selected, and it is understood thateach specific term comprises all equivalents.

FIGS. 1 and 2 illustrate a hockey stick blade 10 constructed inaccordance with the invention. The blade 10 comprises a shank 12, a heelsection 14 and a blade element 16. The heel section 14 is located at thejunction of the shank 12 and the blade element 16. The shank 12comprises a tenon 18 adapted to be inserted into a hollow hockey stickshaft made of aluminum, composite or graphite. It is understood thatinstead of having the tenon 18, the shank 12 can be integrally formedwith a hockey stick shaft.

The blade 10 comprises a top edge 20, a tip edge 22 and a bottom edge24. The blade 10 also comprises a front surface 26 defined by the frontsurface of the blade element 16 and the front surface of the shank 12;and a rear surface 28 defined by the rear surface of the blade element16 and the rear surface of the shank 12.

As shown in FIGS. 3 and 4, the blade 10 comprises a core 30 extendingalong a longitudinal axis A-A. The core 30 comprises a first portion 32located above and aligned with a second portion 34. The first and secondportions 32, 34 are dimensioned such as to have the shape of a bladewhen aligned with one another.

The first portion 32 comprises a bottom surface 36 and extends from theheel section 14 to the tip edge 22. The first portion 32 is generallydelimited by its bottom surface 36 and the planes defined by the top andtip edges 20, 22. The second portion 34 comprises a top surface 38 andextends from the heel section 14 to the tip edge 22. The second portion34 is generally delimited by its top surface 38 and by the planesdefined by the bottom and tip edges 24, 22. As shown in FIG. 3, thefirst and second portions 32, 34 may further comprise respective shankportions 40, 42 defining the core of the shank 12, these shank portions40, 42 comprising respective tenon portions 44, 46. The shank portions40, 42 generally extend upwardly and rearwardly from the heel section14. Hence, the core 30 comprises the first portion 32 with its shankportion 40 and the second portion 34 with its shank portion 42.

It is understood that the core may comprise first and second portionsthat do not comprise respective first and second shank portions. Infact, the first and second portions of the core may be confined to theblade element of the hockey stick blade (from the heel section to thetip edge) and the shank may be a separate component that is joined tothe blade element. For example, the shank may be made of wood andcomprises a groove in which a tongue portion provided on the bladeelement is inserted for joining together both components.

The first and second portions 32, 34 are made of synthetic material suchas a thermo-expandable foam selected in the group consisting ofpolyurethane foam, ethylene vinyl acetate (EVA) foam, polyvinyl chloride(PVC) foam, ethylene polypropylene foam and polyisocyanurate foam. Forexample, the first and second portions 32, 34 may be made ofthermo-expandable polyurethane foam sold by General PlasticManufacturing. The first and second portions 32, 34 may be cut from asheet of foam. Liquid foam may also be injected in a mold in order toform the first and second portions 32, 34.

The second portion 34 may be made of foam having a higher density thanthe one of the first portion 32. For example, the first portion 32 maybe made of foam having a density of between 6 to 12 lbs/cubic foot whilethe second portion 34 may be made of foam having a density of between 14to 18 lbs/cubic foot. In one possible embodiment, the first portion 32is made of foam having a density of 10 lbs/cubic foot and the secondportion 34 is made of foam having a density of 15 lbs/cubic foot.

As shown in FIGS. 3 and 4, the bottom surface 36 of the first portion 32and the top surface 38 of the second portion 34 extend generally alongan irregular line. More particularly, the top surface 38 of the secondportion 34 extends beyond the longitudinal axis A-A in the heel regionsuch that the heel region of the blade 10 is mostly made of higherdensity foam. In the tip region, the bottom surface 36 of the firstportion 32 extends beyond the longitudinal axis A-A such that the tipregion of the blade 10 is mostly made of lower density foam in order toreduce the weight of the blade 10.

In another embodiment, the bottom and top surfaces of the respectivefirst and second portions may both extend along the longitudinal axis ofthe blade.

In a further embodiment, the first and second portion 32, 34 may be madeof a thermo-expandable foam of same density.

It is understood that the core 30 may be made of a single piece that isdimensioned such as to have the shape of the blade. This single piecemay be cut from a sheet of foam. Liquid foam may also be injected in amold in order to form a foam core having the shape of the blade.

A method of making the blade 10 is hereinafter described. As shown inFIG. 5, a first fibers braid 48 is wrapped over the first portion 32 anda second fibers braid 50 is wrapped over the second portion 34. As shownin FIG. 6, a third fibers braid 52 is wrapped over the second fibersbraid 50 of the second portion 34. As shown in FIG. 7, a fourth fibersbraid 54 is wrapped over the first and third fibers braids 48, 52 of thefirst and second portions 32, 34 such as to realize a preformed blade 56as illustrated in FIG. 8. Note that the preformed blade 56 has thegeneral shape of a straight hockey stick blade and comprises front andrear faces 58, 60.

The fibers braids 48, 50, 52, 54 are expandable so as to conform to theshape of the first and second portions 32, 34 and are made of wovenfibers selected from the group consisting of carbon fibers, glassfibers, KEVLAR fibers, ceramic fibers, boron fibers, quartz fibers,spectra fibers, polyester fibers and polyethylene fibers. For instance,a 3K carbon fibers braid, medium weight, commercialized by A & PTechnology or Eurocarbon may be used. Moreover, the fibers braids 48,50, 52, 54 may be made of fibers crossing at 45°. However, any otherfibers crossing at between 30° and 60° may be used. Alternatively,layers of uni-directional or woven fiberglass, layers of uni-directionalor woven carbon fibers or sheets of fibers may be used for covering thecore 30. In another alternative construction, pre-impregnated expandablefibers braids may be used for covering the core 30.

FIG. 9 shows a cross section view of the preformed blade 56 forillustrating the fibers braids before the molding process.

As shown in FIG. 10, front sheet 62 and rear sheet 64 are used forcovering the respective front and rear faces 58, 60 of the preformedblade 56 in the construction of a blade 10. The sheets 62, 64 are madeof a thermoplastic material selected in the group consisting ofpolyethylene, polyurethane, polypropylene, polyester, polystyrene,polyvinyl chloride and cellulose acetate. For example, the thermoplasticsheets 62, 64 may be made of thermoplastic polyurethane (TPU) sheetssold by Isosport IS under the name ISOCAP (density of 1.11 gr/cc andhardness of 73D) or sold by Dow Chemical (density of 1.15-1.25 gr/cc andhardness of 73D).

Each of the thermoplastic sheets 62, 64 may have a contour that isslightly larger than that of the preformed blade 56 such that portionsof the thermoplastic sheets 62, 64 covers the edges of the preformedblade 56. One of the sheets 62, 64 may comprise an indicia 66 that hasbeen marked, engraved or printed thereon as shown in FIG. 10 (see thetrade-mark SWOOSH Design of Nike). It is also understood that thecontour of the sheets of thermoplastic material may be smaller than thatof the preformed blade 56. Moreover, the sheets of thermoplasticmaterial may only recover specific regions of the preformed blade 56.For example, only the regions of the preformed blade 56 that are moresubject to impacts may be recovered with the sheets of thermoplasticmaterial. In one embodiment, only the front face 58 may be recoveredwith a sheet of thermoplastic material; and such a sheet may entirelyrecovers the front face 58, or only a specific region of this front face58 (only the heel region of the front face for example).

The preformed blade 56 and the thermoplastic sheets 62, 64 areafterwards inserted in a mold having the shape of the blade 10. Asuitable resin (urethanes, araldite epoxy, vinylester, polycyanate orpolyester resin) is then injected into the mold to impregnate theexpandable fibers braids 48, 50, 52, 54 and heat is applied to the mold.A resin such as the resin sold by Ciba Specialty Chemicals Inc. underthe name RESINFUSION may be used. The temperature of the mold may bebetween 85° C. and 125° C., the injection pressure of the resin may bebetween 25 psi and 75 psi and the injection temperature of the resin maybe between 20° C. and 30° C. A vacuum pump may be mounted on the moldfor easing the flow of resin through the fibers braids. Owing to theshape to the internal cavity of the mold, the preformed blade 56 iscurved to any desired curvature typically used by hockey players such asto obtain the blade 10.

When the resin is cured, the mold is opened and the blade 10 is removed.Excess resin and material along the edges of the blade are removed withquick trimming and sanding operations.

Once the resin is injected in the fibers braids and the fibers-resinmatrix is cured (see large lines on FIG. 4), the blade 10 comprises aninterface between the first and second portions 32, 34, this interfacecomprising fibers oriented transversely relative to the longitudinalaxis A-A.

As best shown in FIGS. 2 and 4, the blade 10 comprises (a) the core 30formed of the first and second portions 32, 34; (b) a layer of fibers 68recovering the core 30, this layer being formed of a first layer offibers comprising the fibers braids 48, 50, 52 and a second layer offibers comprising the fibers braid 54; and (c) a layer of thermoplasticmaterial 70 recovering the layer of fibers. It is understood that, whenthe resin is cure, the layer of fibers 68 comprises fibers impregnatedinto the resin (see large lines in FIG. 4).

The layer of thermoplastic material 70 comprises the front and rearsheets 62, 64 and forms part of the front and rear surfaces of the bladeelement 16 and the front and rear surfaces of the shank 12 (i.e. frontand rear surfaces 26, 28). In other words, the front 10 and rearsurfaces of the blade element 16 and the shank 12 comprise the layer ofthermoplastic material 70, more precisely, the respective front and rearthermoplastic sheets 32, 34. Should the front and rear thermoplasticsheets 62, 64 have a shape that is slightly larger than that of thepreformed blade 56, then the layer of thermoplastic material 70 may alsocover the edges of the preformed blade 56 and forms part of the edges20, 22, 24 of the blade 10.

As indicated previously, the contour of the thermoplastic sheets 62, 64may be smaller than that of the preformed blade 56 such that the layerof thermoplastic material may only cover specific regions of the blade10. For example, only the regions of the blade 10 that are more subjectto impacts may be covered with the layer of thermoplastic material. Inone embodiment, only the front surface 26 of the blade may be formed ofa thermoplastics layer. Indeed, it is known that the front surface ofthe blade is more subject to impacts. In another embodiment, onlyspecific regions of the front surface 26 may be formed of athermoplastic layer (only the heel and middle regions of the blade 10for example).

Because the front and rear surfaces 26, 28 of the blade 10 comprises thelayer of thermoplastic material 70, the impact resistance of the blade10 is greater than that of a blade having no external layer ofthermoplastic material. For example, for the same blade construction,drop tests shown that the impact resistance increases of at least 50%for a blade having an external layer formed of a thermoplasticpolyurethane (TPU) sheet sold by Isosport IS under the name ISOCAP andat least 70% for a blade having an external layer formed of athermoplastic polyurethane (TPU) sheet sold by Dow Chemical (density of1.15-1.25 gr/cc and hardness of 73D).

The above description of the embodiments should not be interpreted in alimiting manner since other variations, modifications and refinementsare possible within the spirit and scope of the present invention. Thescope of the invention is defined in the appended claims and theirequivalents.

1. A hockey stick blade with a shank and a blade element having a frontsurface and a rear surface, said hockey stick blade comprising; (a) acore of synthetic material extending along a longitudinal axis; (b) alayer of fibers recovering at least partially said core of syntheticmaterial; and (c) a layer of thermoplastic material recovering at leastpartially said layer of fibers, said layer of thermoplastic materialforming part of one of said front and rear surfaces of said bladeelement.
 2. A hockey stick blade as defined in claim 1, wherein saidcore comprises a blade element portion and a shank portion with a tenonportion.
 3. A hockey stick blade as defined in claim 2, wherein saidlayer of fibers also recovers said shank portion of said core.
 4. Ahockey stick blade as defined in claim 3, wherein said layer ofthermoplastic material form part of said front and rear surfaces of saidblade element.
 5. A hockey stick blade as defined in claim 4, whereinsaid shank comprises a front surface and a rear surface, said layer ofthermoplastic material also forming part of said front and rear surfacesof said shank.
 6. A hockey stick blade as defined in claim 5, whereinsaid layer of thermoplastic material comprises a front thermoplasticsheet and a rear thermoplastic sheet, said front and rear thermoplasticsheets forming part of said respective front and rear surfaces of saidblade element and said shank.
 7. A hockey stick blade as defined inclaim 6, wherein said sheets of thermoplastic material are made ofthermoplastic material selected from the group consisting ofpolyethylene, polyurethane, polypropylene, polyester, polystyrene,polyvinyl chloride and cellulose acetate.
 8. A hockey stick blade asdefined in claim 7, wherein said core is made of thermo-expandable foamselected from the group consisting of polyurethane foam, ethylene vinylacetate (EVA) foam, polyvinyl chloride (PVC) foam, ethylenepolypropylene foam and polyisocyanurate foam.
 9. A hockey stick blade asdefined in claim 8, wherein said core comprises a first portion locatedabove a second portion;
 10. A hockey stick blade as defined in claim 9,wherein said layer of fibers comprises a first fibers braid coveringsaid first portion and a second fibers braid covering said secondportion.
 11. A hockey stick blade as defined in claim 10, wherein saidlayer of fibers further comprises a third fibers braid covering saidsecond fibers braid.
 12. A hockey stick blade as defined in claim 11,wherein said layer of fibers further comprises a fourth fibers braidcovering said first and third fibers braids.
 13. A hockey stick blade asdefined in claim 12, wherein said first, second, third and fourth fibersbraids are made of woven fibers selected from the group consisting ofcarbon fibers, glass fibers, KEVLAR fibers, ceramic fibers, boronfibers, quartz fibers, spectra fibers, polyester fibers and polyethylenefibers.
 14. A hockey stick blade as defined in claim 13, wherein saidfirst, second, third and fourth fibers braids are made of fiberscrossing at between 30° and 60°.
 15. A hockey stick blade as defined inclaim 14, wherein said blade comprises an interface between said firstand second portions, said interface comprising fibers orientedtransversely relative to the longitudinal axis of said core.
 16. Ahockey stick blade as defined in claim 15, wherein said shank comprisesa tenon adapted to be inserted into a hollow hockey stick shaft.
 17. Ahockey stick blade as defined in claim 16, wherein one of said front andrear thermoplastic sheets comprises an indicia.
 18. A hockey stick bladewith a shank and a blade element having a front surface and a rearsurface, said hockey stick blade comprising (a) a core of syntheticmaterial extending along a longitudinal axis; and (b) a layer of fibersrecovering at least partially said core of synthetic material, whereinone of said front and rear surfaces of said blade element comprises alayer of thermoplastic material that recovers at least partially saidlayer of fibers.
 19. A hockey stick blade as defined in claim 19,wherein said front surface of said blade element comprises a layer ofthermoplastic material recovering at least partially said layer offibers, said layer of thermoplastic material comprising a frontthermoplastic sheet.
 20. A hockey stick blade as defined in claim 20,wherein said rear surface of said blade element comprises a layer ofthermoplastic material recovering at least partially said layer offibers, said layer of thermoplastic material further comprising a rearthermoplastic sheet.
 21. A hockey stick blade as defined in claim 21,wherein said core comprises a blade element portion and a shank portionwith a tenon portion and said layer of fibers further recovers saidshank portion of said core.
 22. A hockey stick blade as defined in claim21, wherein said shank comprises a front surface and a rear surface,said front and rear thermoplastic sheets also forming part of saidrespective front and rear surfaces of said shank.
 23. A hockey stickblade as defined in claim 22, wherein said thermoplastic sheets are madeof thermoplastic material selected from the group consisting ofpolyethylene, polyurethane, polypropylene, polyester, polystyrene,polyvinyl chloride and cellulose acetate.
 24. A hockey stick blade asdefined in claim 23, wherein said core is made of thermo-expandable foamselected from the group consisting of polyurethane foam, ethylene vinylacetate (EVA) foam, polyvinyl chloride (PVC) foam, ethylenepolypropylene foam and polyisocyanurate foam.
 25. A hockey stick bladeas defined in claim 24, wherein said layer of fibers comprises a fibersbraid and epoxy.
 26. A hockey stick blade as defined in claim 25,wherein said fibers braid is made of woven fibers selected from thegroup consisting of carbon fibers, glass fibers, KEVLAR fibers, ceramicfibers, boron fibers, quartz fibers, spectra fibers, polyester fibersand polyethylene fibers.
 27. A hockey stick blade as defined in claim26, wherein said fibers braid is made of fibers crossing at between 30°and 60°.
 28. A hockey stick blade as defined in claim 27, wherein saidshank comprises a tenon adapted to be inserted into a hollow hockeystick shaft.
 29. A hockey stick blade as defined in claim 28, whereinone of said front and rear thermoplastic sheets comprises an indicia.